linux/debian/patches/bugfix/x86/drm-i915-quietly-reject-att...

53 lines
2.0 KiB
Diff

Subject: drm/i915: Quietly reject attempts to create non-pagealigned stolen
objects
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 10 Dec 2014 08:17:11 +0000
Origin: http://patchwork.freedesktop.org/patch/38659/
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=86883
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=763155
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764528
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=768027
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=771227
This added as a BUG_ON as it considered that no one would ever request
an unaligned object. However, it turns out that some BIOSes will
allocate a scanout that is offset from 0 and not aligned to a page
boundary, and we were passing this through and hitting the BUG_ON during
boot.
Quietly reject such a request to reserve the unaligned stolen object and
let the boot continue, restoring previous behaviour (i.e. no BIOS
framebuffer preservation).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86883
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com)
Tested-by: Johannes W <jargon <at> molb.org>
---
drivers/gpu/drm/i915/i915_gem_stolen.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -431,13 +431,15 @@ i915_gem_object_create_stolen_for_preall
DRM_DEBUG_KMS("creating preallocated stolen object: stolen_offset=%x, gtt_offset=%x, size=%x\n",
stolen_offset, gtt_offset, size);
- /* KISS and expect everything to be page-aligned */
- BUG_ON(stolen_offset & 4095);
- BUG_ON(size & 4095);
-
if (WARN_ON(size == 0))
return NULL;
+ /* KISS and expect everything to be GTT page-aligned */
+ if ((stolen_offset | size) & 4095) {
+ DRM_DEBUG_KMS("request for unaligned stolen object, denied\n");
+ return NULL;
+ }
+
stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
if (!stolen)
return NULL;